Ice-sounding airborne synthetic aperture radar depth profiles from Recovery Ice Stream 2016/17 and Rutford Ice Stream 2019/20 to test the RGB-Doppler-Decomposition method.

This data set corresponds to data acquired by the British Antarctic Survey (BAS) airborne Synthetic Aperture Radar (SAR) PASIN2 (Polarimetric Airborne Scientific INstrument, mark 2), designed for deep ice sounding and basal 3d-mapping. The data set includes the processed SAR images as depth profiles in the Recovery Ice Stream and Rutford Ice Stream, respectively downstream and upstream of the grounding line, and respectively for the 2016/17 FISS (Filchner Ice Shelf System) and the 2019/20 BEAMISH (Bed Access, Monitoring and Ice Sheet History) projects, both during the Antarctic Summer. With multiple antennas for transmission and reception at 150-MHz central frequency, and an across-track physical array, PASIN2 resolves the ambiguities for distinguishing between scatterers from port and starboard directions; however, in the two SAR images of the current dataset the port/starboard ambiguities are not resolved. On this dataset the user will be able to apply the RGB Doppler Decomposition method in the Doppler domain, interpret the results, and modify the different parameters and colours to contrast the results, all with the outcome of conducting new decompositions according to other datasets and needs. The RGB Spectral Decomposition is a generalised framework to interpret the SAR images: first, the Doppler or range spectral domains are first split into three sub-bandwidths; next, to each of the three a colour of a triplet of colours is assigned; and finally the three are superposed into one single image by the addition of the three colours. If the decomposition is applied on the Doppler spectrum, the new image contains the directional information related to the Doppler frequencies: positive frequencies when the radar approaches the target, near zero frequencies when the relative distance from radar to target is near stationary, and negative when the radar leaves it behind. If the backscattering is characterised by a very broad beamwidth the target will be gray/white, and if by a very narrow beamwidth then the target will be represented by one of the colours of the triplet.

This work has received funding from the NERC grant NE/L013444/1, project: Ice shelves in a warming world: Filchner Ice Shelf System (FISS), Antarctica.
The 2016/17 data were collected as part of the NERC grant NE/L013770/1, project: Ice shelves in a warming world: Filchner Ice Shelf System (FISS), Antarctica.
The 2019/20 data were collected as part of the BAS National Capability contribution to the NERC/NSF International Thwaites Glacier Collaboration (ITGC) program.